Flash bulb unit

ABSTRACT

A flash bulb unit which comprises at least two rows of needleshaped combustion flash bulbs arranged in parallel on a common support, in the proximity of which bulbs reflector systems are arranged, the direction of reflection of the reflectors of the bulbs of one row being directed opposite to that of the reflectors of the bulbs of the other row. The flash bulb unit has fusing strips which electrically connect each bulb to the flash circuit for firing the lamps in sequence.

United States Patent 1191 Heeman et a1.

FLASH BULB UNIT Assignee: U.S. Philips Corporation, New

York, N.Y.

Filed: Nov. 2, 1971 Appl. No.: 194,959

Foreign Application Priority Data Nov. 6, 1970 Netherlands 7016259 US. Cl. 240/1.3, 431/95 Int. Cl. G03b 15/02 Field of Search 240/13; 95/11 L; 431/93, 95

References Cited UNITED STATES PATENTS 2/1917 John 240/13 1 Nov. 20, 1973 3,500,732 3/1970 Nijland et a1. 240/13 X 3,598,985 8/1971 Harnden et a1... 240/13 3,619,590 11/1971 Meulemans et a1... 240/13 3,583,304 6/1971 Brandt 240/13 X 3,459,933 8/1969 Prijn 240/13 3,545,904 12/1970 Brandt 240/l.3 X

Primary ExaminerFred L. Braun Attorney-Frank R. Trifari [5 7 ABSTRACT 4 Claims, 5 Drawing Figures PAIENIEUnuvzo I973 SHEET 1 CF 4 IXVEXTORS 2 AGENT PATENIEDnnvzo 1975 3; 774,020

I NVE N TORS AN FLASH BULB UNIT The invention relates to a flash bulb unit comprising a number of combustion flash bulbs which can be ignited by the short-lasting application of a high voltage, said flash bulbs being arranged on a common elongate support, the said flash bulb unit furthermore comprising reflectors which cooperate with the bulbs. Such a unit is particularly suitable for the ignition without the use of a battery of a number of combustion flash bulbs and is described in the Dutch published Pat. application No. 6,613,816.

In the known unit, the lamps which are connected electrically in parallel are arranged in a single row on a common support.

It is the object of the invention to provide, starting from the known unit, a very compact unit in which a comparatively large number of lamps is accommodated.

For that purpose, the unit according to the invention is characterized in that at least a part of the bulbs which have a longitudinal dimension which is from 3 to times larger than the inner diameter and at least a part of the reflectors are secured in the support in two parallel rows, the directions of reflection of the two rows of reflectors being opposite to each other and oriented opposite to each other. In this unit, so-called needleshaped high-voltage flash bulbs are used which are arranged in parallel rows parallel to each other. The flash bulb unit is preferably formed so that the two rows of reflectors are formed by members of a reflecting material which are arranged back-to-back and are closely surrounded by an envelope of a synthetic resin which is transparent at the area of the reflectors and is secured to the support with the reflectors incorporated therein. When the bulbs of one series have been fired, the unit is detached from the camera, rotated through 180 and again secured to the camera, after which the second series of bulbs can be fired.

Also as a result of the use of rather thin needleshaped combustion flash bulbs the possibility is thus presented of constructing the flash bulb unit as a flat flash bulb set which, when not in use, can easily be packed away in a coat pocket as a substantial box. When all the bulbs have been fired, said set is thrown away.

An even flatter unit can be obtained when an embodiment is used which is characterized in that, calculated in the longitudinal direction of the support, a reflector of one reflecting member is present beside a reflector of the other reflecting member. When the flash bulb unit is formed in this manner, there is a minimum loss of effective space between the reflectors.

When using the needle-shaped flash bulbs and with a given requirement that the smallest dimension of the flash bulb set may not exceed a given value, a form of a reflector having a parabolic cross-section in the focus of which the bulb is arranged can no longer be used. This would result in the flash bulb set having a smaller number of flash bulbs or, if each bulb would be arranged outside the focus of its reflector, in an insufficient light reflection. A liminous efficiency which is satisfactory in every respect can all the same be obtained, however, when an embodiment is used which is characterized in that each reflector is constructed from at least three elongate continuous flat parts extending parallel to the bulb axis, the central one of said parts extending behind the bulb in the longitudinal direction of the support and the outermost parts assuming a position in which they are bent towards each other in the direction of the bulb.

The cap of each needle-shaped bulb in the flash bulb unit according to the invention is secured in the support of the unit. Also due to the length of the bulb it is recommendable to also fix the head of the lamp in an unambiguous manner relative to the reflector. For that purpose, the envelope of synthetic resin comprises a number of cavities in which the tips of the bulbs bear.

The flash bulb unit according to the invention may be used for high-voltage flash bulbs which are suitably connected electically with the interposition of a number of switching elements in such manner that they can be fired one after the other by the short-lasting application of a high voltage. Such lamps may then be arranged, for example, in series. However, the invention may be applied in particular to a flash bulb unit in which the bulbs are connected electrically in parallel in a manner as is described in the above-mentioned Dutch published Pat. application No. 6,613,816. With this arrangement it is ensured, without the addition of separate switching elements, that the lamps are fired one after the other.

central conductor being connected to the remaining pole wires of the bulbs of the two rows, a part of the said three conductors projecting beyond the unit. It will be obvious that in spite of the multiplicity of bulbs on the support, a minimum number of electric connections is necessary, which results in a very simple construction of the support. The assembly of the conductors is considerably simplified by providing said support with a number of parallel extending slots in which juxtaposed electrical conductors are incorporated.

f In order to simplify the assembly of the flash bulb ing strip arranged in the proximity of said bulb and incorporated in the current path of one of the pole wires of the bulbs. Said strip will blow as a result of the thermal energy released during firing the bulb, so that the lamp does no longer form part of the electric parallel circuit. Such a method is described in the prior Dutch Pat. application, No. 6,908,333.

An embodiment of the flash bulb unit according to the invention having such-fusing strips is characterized in that the fusing strip is arranged on the outside of the bulb, the strips for a row of bulbs being each connected with their one end to one of the pole wires and being connected with their other end to the central conductOI'.

The invention furthermore provides an embodiment which is characterized in that the central conductor is formed by two electric metal combs which are incorporated with their backs in the support and bear against the fusing strip with their teeth which are formed as resilient lugs and which deform elastically. The combs with the resilient lugs present the possibility of connecting the fusing strips to the central conductor by a clamping connection only. It is not necessary to use conventional connection methods in which a thermal treatment, soldering or the like, is required.

On of the pole wires of each bulb is preferably bent back in such manner as to bear against one of the ends of the fusing strip while deforming elastically. If desirable, other pole wires with the other conductors in the support may also be formed as clamping connections.

In order that the invention may be readily carried into effect, it will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which FIG. 1 is a perspective view of the unit having ten flash bulbs,

FIG. 2 shows, as a partly exploded view, the components of the unit,

FIG. 3 shows the support of the unit having a central conductor in the form of a comb and an outermost conductor having a series of five flash bulbs.

FIG. 4 is a cross-sectional view of the unit taken on the line IV-IV of FIG. 5.

FIG. 5 is a sectional view taken on the line VV of 30 6,613,816). Furthermore, said flash bulbs are needleshaped, the length being from 4 to times as large as the inside diameter of the envelope. The bulbs of each row 3,4 cooperate with reflector members 5 and 6, respectively. The support 2 with the components provided thereon are surrounded by a box-shaped transparent envelope 7 of a synthetic resin.

FIG. 2 shows the support 2 with the rows of bulbs 3, 4. The envelope 7 of synthetic resin with the reflector members 5,6 is shown detached from the support. In this embodiment the support 2 comprises four electric conductors which extend beside each other in the longitudinal direction of the support 2. The central conductors are in the form of combs having a plurality of bent resilient lugs 8. As a result of the resilience of said lugs 8 which press against the wall of the envelope of the bulbs 3,4, the lamps 3,4 assume an inclined position. By means of a metal plate, not shown in the Figure, the central conductors are electrically connected in the bottom 23 of the support 2. For securing the flash bulb unit 1 to a camera, said plate can cooperate FIG. 3 shows the support 2 having four slots 9, 10, 11, 12 extending in the longitudinal direction. The central slots 10 and 1 I serve to receive electric conductors l3 and 14, respectively, comprising the lugs 8. The lugs 8 of the conductor 13 in slot 10 cooperate with the row of flash bulbs 4, which row in the assembled condition is present above the slots 11 and 12. In the same manner the lugs of the conductor 14 in slot 11 cooperated with the bulbs 3 of the row which is present above the slots 9 and 10. Two series of cams 16 and 17 are provided on the part of the support 2 present between the slots 10 and 11. Each of said cams screens the bulb cooperating therewith from the adjacent bulbs of the other row. Searching cams and 21, respectively, are

' provided on the edges 18 and 19 of the support 2. The

assembly of the envelope 7 on the support 2 is facilitated by said searching cams 20 and 21.

The electric conductor 14 having five lugs 8 is shown in a position detached from the support 2. The projection 22 can be threaded through an aperture in the support 2 and contact the metal plate incorporated in the bottom 23.

FIG. 3 furthermore shows the series of bulbs 3. said bulbs are each provided with two pole wires 24 and 25. The pole wires 24 are connected together by a conductor 26. For that purpose, the end of each of the pole wires 24 is bent around the conductor 26 formed from soft copper. When said conductor is present in the slot 9, it contacts a contact member not shown which is incorporated in an aperture passing through the bottom 23 of the support 2 and which debouches beside the metal plate. Each of the pole wires is clamped in a resilient manner against a fusing strip 27 which is arranged against the wall of the bulb envelope. In the assembled condition one of the lugs 8 of the conductor 14 is secured against the part 28 of the fusing strip 27 in a clamping manner. In this embodiment the fusing strip is manufactured from a lead-tin alloy having a melting point of 180 C. As a result of the thermal enwith a coupling system arranged in the upper wall of er gy evolved during firing the lamp, the strip will blow so that the electric contact between the pole wire 25 and the resilient lug 8 of the conductor 14 is interrupted, as is described in detail in Dutch Pat. application No. 6,908,333fThe bulbs are connected to the conductor 26 in such manner that the tips 29 of the bulbs are situated on a straight line and the conductor extends at a prescribed distance from said line. These aligned tips 29 fit in cavities 30 (see FIG. 4) present on .the inside of the envelope 7 in the surface 31. In behalf of the assembly the cavities 30 are conical. As a result of this the bulbs which are slightly forced apart search the center of the cavities when assembling the components shown in FIG. 2, which cavities keep the bulbs at the desirable distance from the reflectors. Dur- -3. The edge 18 of the support 2 comprises the stud 20.

(The cams 21 occurring on the edge 19 are not shown in this Figure to avoid complexity of said Figure). The metal plate 32 is secured in the bottom 23 of the support 2 by means of a screw 33. The support furthermore comprises the slots 9,10,11 and 12. The outermost slots 9 and 12 show widenings 34 at the area of the cams 20 and 21, respectively, for receiving the pole wires 24. Cams 17 are provided on the part 15 of the support 2. The conductor 14 is incorporated in the slot 11 of which conductor the resilient lug 8 bent several times forms part. The projection 22 of the conductor 14 projects through the aperture 34 recessed in the support. The end 35 of the projection 22 is bent and clamped between the metal plate 32 and the bottom 23. The pole wire 24 of the flash bulb 3 is bent around the electric conductor 26 accommodated in the slot 9. This conductor is connected in a clamping manner to the contact member 43 which is accommodated in an aperture 36 recessed in the support 2, and which debouches in the bottom 22 beside and electrically insulated from the plate 32. The fusing strip 27 is secured against the outer wall of the bulb envelope. This fusing strip couples the pole wire 25 which is clamped against the lower part 37 of the fusing strip 27 and the lug 8 of the conductor 14, which lug is clamped against the upper part 28 of the fusing strip. Shown in this Figure are furthermore the electrical conductors 13 and 44, respectively, incorporated in slots and 12, respectively.

The bulbs of the row 4 not shown in FIG. 4 are also connected to the plate 32 by means of a pole wire, a fusing strip and the conductor 13. The other pole wire of the bulbs of row 4 is connected, by means of the con ductor 44, to a contact member which is located opposite to the contact member 43 diametrically relative to the center of the plate 32 and debouches in the bottom 23 of the support 2.

As shown in FIG. 5, the two identical reflector members 5 and 6 are each constructed from 5 reflectors. In this embodiment each reflector is constructed from 5 surfaces extending parallel to the longitudinal axis of the flash bulb to be incorporated in said reflector. As shown in this Figure, the surface 38 which forms part of the reflector member 5 is arranged back-to-back against the surfaces 39 which forms part of the reflector member 6. As a result of this a very compact flash bulb unit is obtained. The outermost surfaces 40 are provided at their ends with the inclined surfaces 41 increasing the luminous efficiency (see also FIG. 2). The projections 42 ensure a clamping fit of the reflector members 5 and 6 in the transparent envelope 7. In this embodiment the reflector members are manufactured by means of injection moulding from a transparent synthetic resin, the reflecting layer being provided by means of vapour deposition.

The assembly of the components is carried out as follows: The elongate flash bulb is provided, with a fusing strip, for example, by means of an adhesive, or by locally liquiefying a layer of lacquer present on the wall of the envelope, and then pressing wall. A series of five flash bulbs extending mutually in parallel is then placed in a holder in such manner that the tips 29 of the bulbs are in alignment. The pole wires 24 are then bent around the conductor 26, said conductor extending parallel to the striaght line on which the tips of the lamps are located. The pole wires 25 are bent against the parts 28 of the fusing strips 27.

The conductors 13 and 14 are arranged in the slots 10 and 11 of the support and locked by means of the metal plate 32. The conductors 26, 44 with the rows of the strip against the bulbs 3 and 4 secured thereto are then laid in the slots 9 and 12. The envelope of synthetic resin with the reflector members 5 and 6 arranged therein is finally slid over the bulbs. The searching cavities 30 present in the bottom of the envelope 7 encloses the tips 29 of the bulbs in such manner that the bulbs do not touch the walls of the reflector or the envelope. Of course the unit may also be constructed with a number of flash bulbs differing from 10. Furthermore, the conductors may project beyond the unit on the short side of the support, the support comprising two series of flash bulbs on its two flat sides. A cross-section of the unit taken parallel to the plane of the support 2 may also take the form of a parallelogram when the short side of the envelope extends parallel to the side wall of the outer most reflectors and projections 42 are lacking as is denoted in FIG. 5 by the dot-and-dash line.

We claim:

1. A flash bulb unit comprising: a plurality of combustion flash bulbs adapted to being ignited by the short-lasting application of a high voltage, the flash bulbs being arranged on a common elongate support, the flash bulb unit also including reflectors being secured in the support in two parallel rows, the directions of reflection of the two rows of reflectors being opposite to each other, and said reflectors being oriented opposite to each other, each row of bulbs also being connected electrically in parallel, and wherein the support is formed as an elongate support which comprises at least three juxtaposed electrical conductors extending in the longitudinal direction of the support, each of the two outermost conductors being connected to one of the pole wires of each bulb of the same row and the central conductor being connected to the remaining pole wires of the bulbs of both rows, a part of the three conductors projecting beyond the unit, and in which a fusing strip is incorporated inthe current path of one of the pole wires, which strip blows as a result of the thermal energy released during the firing of the lamp and wherein the fusing strip is arranged on the outside of a bulb, the strips for a row of bulbs being each connected with their one end to one of the pole wires and being connected with their other end to the central conductor.

2. A flash bulb unit as claimed in claim 1 wherein the central conductor is formed by two electrically coupled metal combs, said combs having a plurality of parallel teeth and a common element connecting said teeth, said common element being incorporated in the support, said teeth being formed as resilient lugs which deform elastically and are adapted to clamp the fusing strip against the bulb.

3. A flash bulb unit as claimed in claim 1 wherein one of the pole wires of each bulb is bent back in such manher as to bear against one of the ends of the fusing strip while deforming elastically.

4. A flash bulb unit as claimed in claim 1 wherein the side of the support facing the flash bulbs comprises cams extending in the direction of the reflector part present behind each bulb and comprises searching edge of the support.

cams arranged on the 

1. A flash bulb unit comprising: a plurality of combustion flash bulbs adapted to being ignited by the short-lasting application of a high voltage, the flash bulbs being arranged on a common elongate support, the flash bulb unit also including reflectors being secured in the support in two parallel rows, the directions of reflection of the two rows of reflectors being opposite to each other, and said reflectors being oriented opposite to each other, each row of bulbs also being connected electrically in parallel, and wherein the support is formed as an elongate support which comprises at least three juxtaposed electrical conductors extending in the longitudinal direction of the suPport, each of the two outermost conductors being connected to one of the pole wires of each bulb of the same row and the central conductor being connected to the remaining pole wires of the bulbs of both rows, a part of the three conductors projecting beyond the unit, and in which a fusing strip is incorporated in the current path of one of the pole wires, which strip blows as a result of the thermal energy released during the firing of the lamp and wherein the fusing strip is arranged on the outside of a bulb, the strips for a row of bulbs being each connected with their one end to one of the pole wires and being connected with their other end to the central conductor.
 2. A flash bulb unit as claimed in claim 1 wherein the central conductor is formed by two electrically coupled metal combs, said combs having a plurality of parallel teeth and a common element connecting said teeth, said common element being incorporated in the support, said teeth being formed as resilient lugs which deform elastically and are adapted to clamp the fusing strip against the bulb.
 3. A flash bulb unit as claimed in claim 1 wherein one of the pole wires of each bulb is bent back in such manner as to bear against one of the ends of the fusing strip while deforming elastically.
 4. A flash bulb unit as claimed in claim 1 wherein the side of the support facing the flash bulbs comprises cams extending in the direction of the reflector part present behind each bulb and comprises searching cams arranged on the edge of the support. 